1. Field of the Invention
The present invention is in the field of the automotive industry and pertains particularly the area of carburetor devices for reducing emissions, and pertains more particularly to devices and methods for preventing gasoline fumes from leaving a carburetor when the associated vehicle is stalled.
2. Discussion of the State of the Art
It is well known that vehicle exhaust emissions from internal combustion engines and fumes from raw gasoline and other combustible fuels are a source of pollution and environmental concern. Regulations exist and are continually enhanced and upgraded by various governmental sources, from local to national level.
One area of growing concern is the area of evaporation of raw fuel, such as gasoline, from vehicle fuel systems. These emissions can be either from the storage tanks used for carrying fuel with a vehicle, or from fuel delivery systems used to deliver fuel to a carburetor device for mixing with air and providing to a an internal combustion engine. In the latter case, when a vehicle is in use, air is typically drawn from outside into a carburetor and mixed with fuel, such as gasoline. The flow of air into the carburetor in this instance effectively blocks back streaming of fuel vapor from the carburetor into the surrounding air. When the same vehicle is stopped, however, and the engine is off, raw fuel still in the carburetor will typically evaporate and back-stream from the carburetor into the local environment. The present invention deals with this back streaming, and the invention taught in one embodiment described below effectively ends back-streaming of fuel under these circumstances.